Magnetic Morphogenesis of Programmable Photonic Architectures through Field‐Directed Droplet Engineering

The creation of dynamically tunable hierarchical architectures in photonic materials represents a crucial frontier in nanoscale science, yet deterministic multi-scale structural control under non-equilibrium conditions persists as an unresolved core limitation despite advances in field-guided assembly technologies. This study demonstrates a magnetic morphogenesis platform combining field-driven droplet deformation and non-equilibrium colloidal assembly to resolve multi-scale structural control. Systematic phase mapping (100-1500 G, 0.1-3.0 wt.%) defines four regimes: spherical, drum-like, ellipsoidal, and belt-like geometries. Through integrated phase-field modeling and multi-scale experimental validation, predictive phase diagrams are established linking external parameters to metastable architectures including lamellar walls, tubular scrolls, and photonic crystal supraparticles with distinct morphological transitions. Resulting photonic crystals exhibit gradient lattice periodicities for magnetically tunable optical anisotropy (480-630 nm) and polarization gating (>95% efficiency over 100 cycles). This work establishes a field-hydrodynamic synergy for designing reconfigurable photonic metamaterials, advancing applications in sensing, optical encryption, and adaptive optics.